Crane boom



D. M. CCPWAN Nov., 2', l?

CRANE BOOM 2 Sheets-Sheet l Filed Sept. l2, 1965 D. M. CQWAN CRANEV BOOM 2 Sheets-Sheet 2 IVENTOR.' DAvlD M.- COWAN Nov. 2l, 1967 Filed sept. 12, 196e United States Patent O 3,353,686 CRANE BOOM David M. Cowan, Deerfield, Ill., assignor to The Hy- Dynamic Co., Lake Bluff, Ill., a corporation of Illinois Filed Sept. 12, 1966, Ser. No. 578,712 Claims. (Cl. 212-55) This invention relates to a crane boom, and, more particularly, to a crane adapted for mobile operation.

A problem has arisen in a telescoping type of crane in providing a suitable installation of the hydraulic cylinder employed for extending the crane boom. Another consideration bearing on the problem of placement and housing of the hydraulic cylinder is that provision should be made for adding an extension to the boom to provide versatility in models without substantial structural changes to the basic boom and cylinder configuration. It is further considered desirable in the boom configuration having the greatest number of extensible members that the reduction in diameter of succeeding sections of reduced cross section be as small as possible in order to obtain maximum resistance to column iiexure of a fully extended boom under heavy load by employing a preferred type of bearing arrangement.

The main object of the present invention, therefore, is to provide a configuration for an extensible crane boom and hydraulic cylinder assembly wherein the cylinder is situated to allow for adding a boom extension, if desired, and wherein a single hydraulic cylinder is all that is required in any configuration to minimize the reduction in diameter of succeeding boom segments.

FIG. 1 is an elevational viewof a mobile crane constructed according to the teachings of the instant invention;

FIG. 2 is a fragmentary sectional view of the crane portion of the device seen in FIG. l;

FIG. 3 is an enlarged sectional View taken along the line 3-3 of FIG. 2;

FIG. 4 is an enlarged sectional View taken along the line 4 4 of FIG. 2;

FIGS. 5, 6 and 7 are schematic sectional views of a modied form of crane showing the parts thereof in different operative conditions;

FIG. `8 is an enlarged fragmentary view of the cantilever end o-f the boom; and

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 2.

In the illustration given and with reference to FIG. 1, the numeral 10 designates generally a mobile crane which is equipped with a tractor-type chassis 11. The numeral 12 designates a turntable which is mounted on a pedestal 13 for rotating the turntable 12 about a vertical axis.

The numeral 14 designates a shipper or outer member of the crane assembly which is mounted on the turnta'ble 12 as at 15 for pivoting about a horizontal axis. The means for pivoting the shipper 14 about the horizontal axis defined 'by the pivot 15 are a pair of hydraulic cylinders, one of which is seen in FIG. l and designated 16. The numeral 17 designates a counterweight, while the numeral 18 designates a Winch mechanism for the cable running to the crown assembly 19 which is provided on the cantilever end 20a of the boom Referrin-g now to FIG. 2, which illust-rates in more detail a preferred embodiment of the extensible boom 20 adapted to be expanded by adding a boom extension as explained below, it is seen that the boom 20 is telescopically received within the shipper 14. The means for extending the boom 20 can be seen in the form of a cylinder and piston rod unit 21 having a butt end 22 pivotally mounted on pin 23 to the shipper 14. The numeral 24 designates a piston rod and this is connected to a puller ICC tube 25 employed to extend the boom 20' relative to the: shipper 14 (see FIGS. 3 and 4).

It will be noted that the shipper 14, boom 20, puller tube 25 and cylinder and piston rod unit 21 are all located along the same axis. It will be further noted that suicient space is provided between puller tube 25 and boom 20, as seen at the break in FIG. 2 and designated generally at 25a, for the addition of a boom extension member as explained below in connection with the description of FIGS. 5-7.

For the purpose of extending the boom 20, a piston rod 24 is equipped with an eye 26 which receives a piston rod pin 27 (see also FIG. 4). The piston rod pin 27 is journalled within a spherical bushing 26a mounted in eye 26. Pin 23 that pivotally mounts the butt end 22 of the cylinder is also journalled within a spherical bushing similar to 26a mounted in butt end 22. The piston rod pin 27 is journalled within journal blocks 28 fixed inside the puller element 25 (see FIG. 4). Thus, as the piston rod 24 is extended out of the cylinder 21, it extends the puller element 25 by acting through the pin 27 and blocks 28. The puller element 25 advantageously may take the form of the tube shown.

The linear motion of the puller tube 25 is coupled to the boom 20 by means of segmental shafts 29 (see FIG. 3). The segmental shafts 29 are boltably secured to the puller tube 25 and are journalled within suitable openings provided within the boom 20. This preferred trunnion connection between puller tube 25 and boom 20, it will be noted, transmits linear motion axially of the boom 20 but does not couple a bending moment between the two which would create an undesirable torsional force in the segmental shafts 29.

In the ordinary instance where no `boom extension member of the character seen in FIGS. 5-7 is'employed, supplemental bearing support for the cylinder 21 and puller tube 25 is provided in the form of bearing pins 31. In FIG. 4, it is seen that the pins 31 are secured to the piston rod pin 27 by means of bolts 32 suitably countersunk within the bearing pins 31. The bearing pins 31 are further seen to be loosely mounted within journal openings 33 which provide the clearance designated 33a. Thus, bea-ring means are provided adjacent the outer end 25a of puller tube 25 to limit sideways and vertical movement of the outer end of the puller tube and the piston rod eye 26, i.e., the two degrees of lateral movement transverse to the length of the elongated puller tube.

Additional bearing means are provided for the rod end of the cylinder unit 21 in the form of a ring-bearing 34 equipped with suitable flat surface-providing shoes as at 35 (see also FIG. 3) which coact with the interior of the puller tube 25 in stabilizing the cylinder 21 at its rod end to limit column flexure, thereby making it possible, by

changing the size of shoe 35, to utilize smaller diameter cylinder and piston rod units `as replacements in the practice of the invention.

It will be noted that the cylinder 21 is substantially housed within the puller tube 25 only a very small portionof the butt end 22 of the cylinder 21 projecting beyond the inner or rearward end of the puller tube 25. When the piston rod 24 is retracted as shown in FIG. 2 so that the puller tube 25 is .at its innermost position, the distance between the pivotal mounting 23 and the pivot access of the segmental shafts 29 is less than about onetenth the length of the cylinder 21. Thus, when the piston rod 24 is fully extended, the cylinder 21 is supported at its butt end 22 as at 23 and also at its piston rod end by means of the shoes 35. This is beneficial in limiting the above-mentioned column exure.

The element next outward of the cylinder 21 is the puller tube 25 and, -as previously brought out, the puller tube 25 is pivotedly connected by means of the segmental shafts 29 to'the boom 20. For this purpose, the segmental shafts 29 are'secured by bolts 30 to bosses 36 (see FIG. 3) welded to the sides of the puller tube 25. The journals for the segmental shafts 29 are provided by additional bosses -as at 3"7y which are weldably secured within side openings provided in the boom 2). Thus, the puller tube is supported at its inner end within the boom 20 and at its outer end is additionally supported in one of two fashions, depending on whether or= not a boom extension is used.

Reference to FIG. 4 reveals the fashion in which the puller tube 25 is supported within the boom 20 when there is no boom extension provided. In thaty model of the device, the bearing ends 31 previously referred to are employed. However, when a boom extension is employed, it will be positioned within the apparatus coaxial with boom 2t) and puller tube 25 at the place indicated by the dotted line in FIG. 4 and designated .by the symbol E. The boom extension may be releasably locked to the boom 20 or may be adjustably fixed to the boom 20 in the fashion indicated in FIGS. 5-7. In lany event, whenever the boom extension E is employed, the bearing pins 31 are removed (merely by removing the bolts 32), in which case the supplemental bearing for the puller tube 25 is achieved by shoes or bearing elements 38 which project vertically upwardly and downwardly from the puller tube 25 vand laterally from both sides as at 39 for engagement with the interior surfaces of the boom extension. Thus, the bearing pins 31 and the shoes 38 and 39 (used alternatively) constitute bearing means adjacent the rod eye 26 of the unit 21 for supporting the rod eye and the outer end 25a of puller tube 25 against lateral and vertical inflection.

When a boom extension is employed, it is advantageous to be able to slide the boom extension a maximum distance back into the boom, thereby shortening the overall length of the machine for transport but allowing a maximum extension length for crane operation. It will be seen that when bearing pins 31 are removed, the boom extension E can be stored in the boom rearward to a point adjacent to the segmental shaftsk 29 that connect the puller tube 25 to the boom 20. Thus, the puller tube device is useful in allowing a maxi-mum length of boom extension to be stored coaxially with Ian interior of the boom 20.

Bearing plates 42 are fastened as by welding to the top surface ofv the inner end of the boom 20 (see FIGS. 2 and 3). The outer end of the Iboom is supported by and slides on shoes 50 that are pivotally mounted on a cylindrical support 51 that is fixed to the outer end of the shipper 14. The combination of bearing plates 42 and shoes 50 are advantageously employed in the illustrated embodiment by providing extended bearing surfaces, as distinguished from the narrow supporting interface provided by a roller bearing for instance, to limit column ilexure in supporting the boom 20 in its extended position when loads `are suspended from the crane. Further, the trunnion mount provided by segmental shafts 29 connecting the puller tube 25 with boom 20 cooperates to transfer all of the load to these bearing surfaces.

To limit the lateral movement of the boom and to provide side bearing surfaces between the boom 20 and the shipper 14, plates 43 are adjustably mounted to the sides of the inner end of the boom 20 (see FIG. 3). Further lateral bearing for the boom is provided at the outer end of the shipper 14 by plugs 52 that are adjustably mounted, as by threading, to the sides of the shipper 14 (see FIG. 9). A similar plug 53 is adjustably mounted on the top surface of the underside of the 4shipper to support the weight of the boom assembly when it slidesV to the contracted position.

From the foregoing, it will be appreciated that the crane hereindescribed is a versatile, adaptable unit. When initial cost considerations dictate, the user may buy the crane as illustrated on the rst drawing Sheet. Particularly FIG. l with merely a boom and no boom extension. Also by having the cylinder with its casing portion attached to the base of the shipper, it is possible to feed the butt end with the hydraulic iluid, resulting in less complicated connections and piping than would be the case if the connections were through the piston rod or if a cylinder unit were arranged to move with each extensible member, `as shown in the prior art. Afterwards, as the need for a longer crane is felt, a boom extension can be readily inserted into the unit, removing the bearing pins 31 and most expeditiously bolting the boom extension to the boom 20 in place of the crown assembly 19. The crown assembly 19 is then transferred to the end of the boom extension E.

Bearing plates similar to those advantageously used in providing a bearing surface between the shipper 14 and the boom 20 as described above, may be used for the sliding t between the boom 20 and the boom extension when it is employed. FIG. 8 shows additional shoes 50 supporting the yboom extension E, with the shoes 50' pivotally mounted on a support 52' that is fixed to the outer end of boom 20.

Additional details ofthe more versatile arrangement is seen in FIGS. 5-7 which are essentially schematic representations of a crane having an extensible boom extension. In FIG. 5, the numeral '114 designates the `shipper and the numeral 121 designates the cylinder and piston rod unit which is vsecured in pivotal fashion to the shipper as at 123. The portion of the unit 121 corresponding to the piston rod 24 is itself a `supplemental cylinder and piston rod unit and is designated 124 being pivotally connected as at 129' to a puller tube 125. This intermediate extensible portion 124 of unit 12.1 is adapted to be completely expanded before the terminal portion, designated as 144 will begin to extend.

The puller tube 12S is connected in the fashion seen in FIG. 3 to the boom 120 and the piston rod I144 of the supplemental unit 124 is pivotally connected as at 145 to the boom extension 146 intermediate its ends. The crown assembly is designated m Thus, there is provided a full range of movement of a completely telescoped boom and boom extension as .seen in FIG. 7 to one that is partially extended as inFIG. 6 to one that is completely extended as in FIG. 5.

When the cylinder configuration is fused with the puller tube design as shown in FIG. 5 to provide hydraulic extension means for both the boom and the boom extension, it will be seen from FIG. 5 that the extended cylinder assembly between pivot pins 123 and 145 is restrained from flexing as a column by the engagement at point A between the rod end of the cylinder 121 and the inner end of the puller tube 125. The extended cylinder assembly is further restrained from flexing as a column by the engagement at point B between the outer end of puller tube and the inner surfaces of the boom extension 146. Thus, the puller tube device, when located axially of the boom and boom extension, is useful in allowing the design of relatively small diameter cylinders and rods with extremely long column lengths between pins 123 and 145.

It will be appreciated that other bearing plates may be provided on various surfaces of the boom and boom extension to provide non-galling sliding engagement between the various members and also to insure proper fits and clearances between the various telescoping members. Further, FIGS. 5-7 illustrate the crane assembly without a detailed showing of the preferred method of attaching the boom extension removably to the boom by removal of the crown assembly as was done in connection with FIG. 8. Also, these figures do not illustrate, as redundant, the preferred shoe arrangements as 50 and 50 of FIGS. v8 and 9.

It will be further seen from FIG. 8 that the cantilever end 20a of the boom 20 is equipped with openings 48 and 49 for the receipt of bolts to secure the crown assembly 19 to the boom 20. When the crown assembly is removed for the installation of a boom extension E, openings in the boom extension E in registration with those designated 48 and 49 in the hoorn will be utilized for connecting the boom extension E in a removably fixed fashion to the boom 20.

While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of explanation, many variations in the details hereingiven may be made by those skilled in the are without departing from the spirit and scope of the invention.

I claim:

1. A crane, comprising a support, a turntable mounted on said support for rotation about a generally Vertical axis, an elongated shipper mounted on said turntable for rotation about a generally horizontal axis, hydraulic means interconnecting said shipper and turntable for set lectively positioning said shipper at various angles relative to the ground, a boom slidably mounted in said shipper for selective extension and retraction relative to said shipper, said boom being adapted to be extended relative to said shipper and having at the outer end thereof a crown assembly operably associated therewith and adapted for selective common movement with said boom, a hydraulic cylinder and piston rod unit located coaxially with and interiorly of said boom with the cylinder portion pivotally connected to the base of said shipper, means connecting the piston rod portion of said unit to said boom, said connecting means including a puller tube mounted coaxially with and interiorly of said boom with said unit being substantially received within said puller element, pin means coupling the piston rod portion of said unit to said puller element adjacent the outer end of said puller element, and segmental shaft means pivotally connecting said puller element to said boom adjacent the inner end of said puller element, said puller element being of smaller diameter than said boom sucient to dene an annular space between said puller element and said boom for telescopically receiving a boom extension coaxially with said boom.

2. The structure of claim 1 in which the distance between the axis of rotation of the pivotal connection of said unit cylinder portion with said shipper and the axis of rotation of the pivotal connection of said segmental shaft means is less than about one-tenth the length of said unit.

3. The structure of claim 2 in which said cylinder adjacent the end of the rod portion of said unit is equipped with bearing means for coaction with the interior of said Ipuller tube to limit column exure of said unit when said rod is extended.

4. The structure of claim 1 further including a bearing plate attached to the top surface of the inner end of said boom for slidably engaging the interior of said shipper, and a bearing shoe pivotally mounted at the outer end of said shipper slidably engaging the lower surface of said boom, whereby said bearing plate and said shoe cooperate to limit column exure when said boom is extended.

5. The structure of claim 1 in which said puller tube is equipped with bearing means adjacent the rod end of said unit for supporting said puller tube against lateral deflection.

`6. The structure of claim 5 in which said bearing means includes pin means loosely journalled within said boom and removably coupled to said puller tube.

7. The structure of claim 5 in which said bearing means includes laterally projecting abutments for coaction with a boom extension telescopically received within said boom.

8. The structure of claim 1 in which boom is equipped with a boom extension telescopically received within said annular space interior of said boom, said crown assembly being xed to said boom extension.

9. The structure of claim 8 in which said unit comprises a double hydraulic extension cylinder including a casing, an intermediate extension member and a terminal extension member, said casing being connected to said shipper and extending interiorly of said puller tube, said intermediate extension member being connected to the outer end of said puller tube, and said terminal extension member being connected to the outer end of said boom extension member.

10. The structure of claim 9 further including a rst bearing plate attached to the top surface of the inner end of Said boom for slidably engaging the interior of said shipper, a rst bearing shoe pivotally mounted at the outer end of said shipper slidably engaging the lower surface of said boom, a second bearing plate attached to the top surface of said boom extension for slidably engaging the interior of said boom, and a second bearing shoe pivotally mounted at the outer end of said boom for slidably engaging the lower surface of said boom extension.

References Cited UNITED STATES PATENTS 3,112,035 11/19613 Knight 212--55 3,243,052 3/1966 Grove 212-55 3,315,821 4/196-7 Grove 212-55 ANDRES H. NIELSEN, Primary Examiner. 

1. A CRANE, COMPRISING A SUPPORT, A TURNABLE MOUNTED ON SAID SUPPORT FOR ROTATION ABOUT A GENERALLY VERTICAL AXIS, AN ELONGATED SHIPPER MOUNTED ON SAID TURNTABLE FOR ROTATION ABOUT A GENERALLY HORIZONTAL AXIS, HYDRAULIC MEANS INTERCONNECTING SAID SHIPPER AND TURNTABLE FOR SELECTIVELY POSITIONING AND SHIPPER AT VARIOUS ANGLES RELATIVE TO THE GROUND, A BOOM SLIDABLY MOUNTED IN SAID SHIPPER FOR SELECTIVE EXTENSION AND RETRACTION RELATIVE TO SAID SHIPPER, SAID BOOM BEING ADAPTED TO BE EXTENDED RELATIVE TO SAID SHIPPER AND HAVING AT THE OUTER END THEREOF A CROWN ASSEMBLY OPERABLY ASSOCIATED THEREWITH AND ADAPTED FOR SELECTIVE COMMON MOVEMENT WITH SAID BOOM, A HYDRAULIC CYLINDER AND PISTON ROD UNIT LOCATED COAXIALLY WITH AND INTERIORLY OF SAID BOOM WITH THE CYLINDER PORTION PIVOTALLY CONNECTED TO THE BASE OF SAID SHIPPER, MEANS CONNECTING THE PISTON ROD PORTION OF SAID UNIT TO SAID BOOM, SAID CONNECTING MEANS INCLUDING A PULLER TUBE MOUNTED COAXIALLY WITH AND INTERIORLY OF SAID BOOM WITH SAID UNIT BEING SUBSTANTIALLY RECEIVED WITHIN SAID PULLER ELEMENT, PIN MEANS COUPLING THE PISTON ROD PORTION OF SAID UNIT TO SAID PULLER ELEMENT ADJACENT THE OUTER END OF SAID PULLER ELEMENT, AND SEGMENTAL SHAFT MEANS PIVOTALLY CONNECTING SAID PULLER ELEMENT, SAID PULLER ELEMENT THE INNER END OF SAID PULLER ELEMENT, SAID PULLER ELEMENT BEING OF SMALLER DIAMETER THAN SAID BOOM SUFFICIENT TO DEFINED AN ANNULAR SPACED BETWEEN SAID PULLER ELEMENT AND SAID BOOM FOR TELESCOPICALLY RECEIVING A BOOM EXTENSION COAXIALLY WITH SAID BOOM. 